Improve i18n link references in docs

[azdanov]

At the moment it's a very hard work to keep the prefixes (/, /de, /es, /fr, etc) and id references (#x86_64-microarchitecture-level-support, #x86_64-mikroarchitektur-level-unterstützung, #soporte-de-nivel-de-microarquitectura-x86_64, #support-du-niveau-de-microarchitecture-x86_64, etc) in sync across translations.

It would be good to figure out a way to minimize the risk of forgetting to update them when updating either by using relative paths instead of absolute and by using English heading id's everywhere instead of localized ones.

• https://docs.astro.build/en/guides/markdown-content/#heading-ids
• https://docs.astro.build/en/guides/internationalization/#create-links